Adjusting apparatus for spring mechanism



Dec. 6, i949 R. w. PAsHBY 2,490,741

ADJUSTING APPARATUS FOR SPRING MECHANISM Filed sept. 25. 194e 1oy sheets-sheet 1 Dec. 6, 1949 Rfw. PASHBY 2,490,741

ADJUSTING APPARATUS FOR SPRING MECHANISM Filed Sept. 25, 14946 l0 Sheets-Sheet 2 Dec. 6, 1949 R. W, PASHBY 2,490,741

ADJUSTING APPARATUS FOR SPRING MECHANISM R- W. PASHBY Dec. 6, 1949 ADJUSTING APPARATUS FOR SPRING MECHANISM Filed Sept. 25, 1946 10 Sheets-Sheet 4 Dec. 6, 1949 R. w. PAsHBY ADJUSTING APPARATUS FOR SPRING MECHANISM 10`Sheets-Sheet 5 Filed' sept. 25, 194e Dec. 6, 1949 R. w. PAsHBY 2,490,741

ADJUSTING APPARATUS FOR SPRING MECHANISM Filedsept. 25, 194e 1o sheets-sheet e 40m/5 T50 I f7() 78C Nc Raf/y Dec. 6, 1949- R. w. PAsHBY 2,490,741

ADJUSTING APPARATUS FOR SPRINGMECHANISM Filed Sept. 25, 1946 lO Sheets-Sheet '7 Dec. 6, 1949 R. w. PAsHBY 2,490,741

ADJUSTING APPARATUS FOR SPRING MECHANISM Filed Sept. 25. 1946 10 Sheets-Sheet 8 @04.1% Jgf Dec. 6, 1949 R. w. PASHBY 2,490,741

ADJUSTING APPARATUS FOR SPRING MECHANISM Filed Sept. 25, 1946 10 Sheets-Sheet 9 Dec. 6, 1949 R, w. PASHBY 2,490,741

ADJUSTING APPARATUS FOR SPRING MECHANISM Filed Sept. 25, 1946 10 Sheeb'S--Sheeb l0 JLJ. 79d

Patented Dec. 6, 1949 UNITED STATES PATENT OFFICE ADJUSTING APPARATUS FOR SPRING MECHANISM Robert W. Pashby, Park Ridge, Ill., assignor to First industrial Corporation,

Wilmington, Del.,

a corporation of Delaware Application September 25, 1946, Serial No. 699,314

23 Claims.

The present invention relates to apparatus for the adjustment of snap acting mechanisms, particularly to the adjustment of snap acting switches, in accordance with the method disclosed and claimed in copending application, Serial No. 699,315, led September 25, 1946.

Hand adjustment of snap acting mechanisms such as employed in small compact snap acting switches has long been a bottleneck in their manufacture. The production of individual parts of these mechanisms as well as their assembly has long been completely mechanized so that one worker can produce thousands of individual parts or assemble thousands of switches per day. But adjustment for desired operating and release forces have been carried out only by painstakingly slow hand work requiring a high degree of skill and entailing much trial and error.

An object of the present invention lies in the provision of apparatus which eliminates this long existing bottleneck by making the adjustment operation completely automatic so that all the operator has to do is feed in the switches to be adjusted. For example, in one specic type of electric switch that the present invention has been applied to, one operator can adjust approximately 3200 switches in a day with the present invention as contrasted with approximately only 400 by the old hand method. Furthermore, the adjustment made by the apparatus of the present invention is far more consistent and accurate than possible with the hand method.

An object of the present invention when appiled to a self-returning type of snap acting mechanism having an overcenter snap spring with a support therefor lies in the provision of apparatus which first loads the spring sufciently to operate it, that is, to move it from normal to abnormal position, then changes the loading to a value dependent upon a desired release force, followed by moving or deforming the support through an axis of maximum stress until the spring snaps back to its normal position.

Another object is the provision of an adjusting apparatus for a self-returning type of snap spring mechanism an example of which is the general kind employed in double throw, normally open, and normally closed switches, the adjusting apparatus including means for initially moving the spring to abnormal position and including an electromagnetic clutch for transmitting a force from an operating member to the spring support while the spring is in abnormal position to permanently move the support through an axis of maximum stress to initiate movement of the 55 spring from abnormal to normal position, the clutch being deenergized in response to movement of the spring to normal position to prevent iurther transmission of force from the operating member to the support.

Another object is the provision of an adjusting apparatus for a snap spring mechanism having an overcenter snap spring system mounted on a support, the mechanism being initially assembled with the support spaced to one side of a certain position preferred for proper operation, the apparatus including means for moving the spring system to abnormal position and then applying a preselected release load to the spring system and means for moving the support in the direction of its preferred position until the spring snaps to normal position to signify the end of the adjusting operation.

A specific object is the provision of a switch adjusting apparatus in which the switch being adjusted is incorporated into the control circuit to automatically terminate the adjusting operation when it has progressed to the point that the switch spring snaps back to its normal position.

Other objects and advantages will become apparent from the following description in connection with the drawings in which Figure 1 is a front view of one form of switch adjusting mechanism embodying the principles of the present invention;

Fig. 2 is a left side view of Figure 1 drawn to a different scale than Figure 1;

Fig. 3 is a right side view of Figure 1 drawn to a diierent scale than Figure 1;

Fig. 4 is a plan view of the mechanism, taken on the line 4-4 of Figure 1;

Fig. 5 is a sectional view of Figure 1, taken on the line 5 5;

Fig. 6 is a sectional view of Figure 1 taken on the line 6 6;

Fig. '7 is a sectional view of Figure 1 taken on the line 7 1;

Fig. 8 is a view of Fig. 2, taken on the line 8 8;

Fig. 9 is a longitudinal, vertical sectional View of one form of electric switch which may be adjusted by the present mechanism;

Fig. l0 is a transverse sectional view of Fig. 9, taken on the line iB l;

Fig. 11 is a perspective bottom view of the switch of Fig. 9, showing the terminal connections;

Fig; 12 is a perspective View of the anchor employed in the Fig. 9 switch;

Fig. 13 is a perspective View of the snap spring system employed in the Fig. 9

switch;

Fig. 14 is a fragmentary, perspective view of the switch holding mechanism and of a switch with cover plate removed as will be the case during adjustment;

Fig. 15 is a partial sectional view of Fig. 14, showing the shoulders and iingers employed to support the switch undergoing adjustment;

Fig. 16 is an end view of Fig. 14 showing the switch housing in place and showing the leaf springs which engage the the switch part of the adjusting circuit;

Figs. 17a, 17h, 17o and 17d are views in the various operative positions of a simplied circuit which may be employed with the present invention for adjusting open switches. This circuit is designated A in the following description.

Figs. 18a, 18h, 18e and Figs. 17-20, respectively,

18d are views similar to and show another Simplified circuit which may be employed with the present invention for adjusting normally closed switches. This circuit is designated B in the following description.

Fig. 19a is a View of a circuit, designated AB in the following description, which combines both #1:'-

the A 'and B circuits so the mechanism 4may be employed to adjust double throw, normally open, or normally closed switches. Figs. 19a, 19h, 19e and 19d show the AB circuit in the various operative positions for adjusting double throw or 1 i normally open switches. Similarly, Figs. 19e, 19j, 19g, Yand 19h show the AB circuit in the various operative positions for adjusting a normal-ly Aclosed switch.

Fig. 20 is an enlarged view oi a portion of Figure l showing the parts in their normal position at thel start of the adjusting operation. This corresponds with the normal position Vof the parts shown in Figs. 19a and 19e.

Fig. 21 is a partial front view similar to Figure l, showing a succeeding operative position, corresponding to Figs. 19h and 191, in which the spring system of the switch being tested is loaded by the weight of both loading arms;

Fig. 21a is an enlarged view of Fig. 2l, similar to Fig. '20;

Fig. 22 is a view similar to Fig. 21 showing a succeeding operative position, corresponding to 19C and 19g, in which the spring system oi the switch being tested is loaded by the weight of only the lower loading arm;

Fig. 22a is an enlarged view of Fig. 22, similar to Fig. 21a;

Fig. 23 is a view similar to Fig. 22 showing a succeeding operative position, corresponding to l Figs. 19d and 19h, in which the support for the spring system is deformed sufficiently to cause the spring to snap to its normal position, and

Fig. 23a is an enlarged view of Fig. 23, similar to Fig. 22a.

Consideration will be given iirst to a representative switch of the compact precision type to which the present invention is applicable. Figs. 9-13, inclusive, show a compact precision type switch of the kind disclosed in McGall Patent 1,960,020 to which reference may be had for details concerning this type of switch. Briefly, it includes an insulating case having a base I and a cover `2; upper and lower stationary contacts I3 and i4, respectively, having terminal screws I5 and I6 and tabs Il and I8; and a movable contact I9 carried by the over-center snap spring system generally designated 2| which is connected at the opposite end to the common terminal screw 22 and tab 23. Terminal bushterminal screws to make double throw `and normally iii) ings 26 and 21 which are preferably molded integral with the base portion I provide support for the stationary contacts as well as providing electrical connection between the stationary contacts and the terminal tabs Il and i8.

The spring member 2| comprises a thin leaf tension element or reed 24 which is connected in cantilever fashion to the terminal bushing 28 by means of a screw 2S. A pair of thin leaf compression elements 3| are joined to the tension element 24 at the movable contact I9 and pivotally supported intermediate the ends of the tension element 24 where they bear against the anchor or supporting member 32. This support member 312 is cut out in the center so as to be left U--shaped to clear the tension member 24 and has a pair oi notches 33 for receiving and pivotally supporting the compression elements 3|. The operation is such that when the plunger 34 is depressed it will move the tension element 24 downward to a position in line withV the pivots 33. This position is a position or axis of maximum stress for the spring system 2| and further depression of. the plunger 34 moving the tension element through this axis will cause the spring to move downwardly of its own accord with a snap action, disengaging the contacts I3 and I9 and engaging lcontacts i4 and I9.; conversely, when the depressive force on` the plunger 34 is released, since in this instance the switch illustrated is ci the self-returning type, the tension element 24 will move upwardly through an axis of maximum stress and the spring system will be caused to return by snap action to the' normal position shown in Fig. 9.

lThe switch adjusting mechanism here shown to illustrate the present invention comprises a frame 36 (Fig. 2) of the general type employed in arbor presses 'and the like having a rotatable shaft 3` engaged within the housing with the vertically reciprocable rack v38, as. by means oi a conventional rack and pinion (not shown), so that rotation of the shaft 31 causes reciprocation of the rack 38. A clutch lever 39 comprising a pair of spaced parallel arms 41| is keyed to oneA end of the shaft 31 and carries van electromagnetic clutch Inemb'er 42 having a coil/43, a core 44 and lead wires 43 rand 4'1. The clutchlever 39 is maintained on the shaft 3l by means of a retaining disk 48 and screwfi. Between the clutch lever ari-ns 4I' an 'operating lever 5I is freely rotatable about the shaft 31., independently thereof, and carries a disk-shaped armature l52 adapted to be attracted by the clutch member 42 when the c'oil e3 is energized.. In this case.. means vfor manual operation is provided in the form of the handle 53 but it will be obvious that suitable motor means may be employed. Opposite the lhandle 53 the end of the lever 5| is vel'orligated to serve the dual purpose of. counterweighting it to seek a position approximately that shown in Fig. 2 'and to operate the normally closed Yswitch |48, hereinafter referred to as the pre-loading switch. The end portion 56 of the operating lever 5| is of sufficient width that it will maintain the prei-loading switch |48 opened when the handle 53 is vpulled downward through its various operating positions to beV described. 'The manner in which the portion 56 of the operating lever is adapted to overrun the pre-loading switch actuating lever '5l to hold it open is best shown in Fig. y8. At the opposite end of the rotatable shaft 3l and held in place by set screws 53 (Fig. 3) is a .pulley sector 59 -having a peripheral 'groove 6i with a wire or cable 62 fastened in`1'ts'1`1`ppe`r end. The wire 62 extends through the aperture 63 in the bench or support 64 and is connected to a weight 66 large enough to move the sector 59 and clutch lever 39 to their normal positions shown in Figs. 3 and 2, respectively, when no torque is applied to the clutch lever through the operating lever 5|. Beneath the weight 66 and connected to it is a double-acting dashpot means for regulating the speed of movement of the weight and hence for regulating the rate of r0- tation of the shaft 31 in both directions. This dashpot means comprises a piston 61 connected to the weight by rod 68, a cylinder 69 preferably lled with a liquid, and a by-pass line 1| connecting the ends of the cylinder. The rotational speed of the shaft 31 is controlled by the position of the by-pass valve 12.

The vertically reciprocable rack 38 has an axially extending ram 'i3 mounted therein by means of a set screw 1li. The end of the rain 13 is formed with a pair of projections 16 (Fig. 5) adapted to contact the anchor legs (designated 11 in Fig. 12) of the switch being adjusted and to bend the anchor downwardly. A stop plate 18 (Fig. 3) fastened to the rack 38 by bolts 19 limits its upward movement by engagement with the under surface 8| of the housing. Fig. 5 also shows the forwardly extending hook member 82 which is mounted on the side of the rack 38, the function of which will be brought out as the description proceeds. Mounted on the housing platform 83 by screws 84 is a plate 86 (Fig. 2) which carries the loading arms 81 and 88 (Fig. 1) for applying pre-selected loads to the switch spring in sequence controlled by the downward movement of the ram 13. At the end of the plate 86 remote from the platform 83 is an upstanding fulcrum member 89 having a pair of spaced vertical columns 9| (Fig. 2) connected by tie bars 92 and 93, the latter being drilled and tapped for mounting on the plate 86 by bolts 94. Each of the loading arms 81 and 88 is fulcrumed between the columns 9| by means of a spacer bushing 96 (see Fig. 7) on which the arm is centered by a press iit, the bushings 96 being trunnioned on small diameter rods 91 which are held posiapertures 98 in the columns 9| rby cotter pins 9 gageable with that portion of the switch spring system that is normally engaged by the plunger 33. In this case the portion of the spring which is engaged by the plunger is near the mounted end of the tension element 24, between the anchor legs 11, as shown in Fig. 9. A transverse pin |62 extending from the arm 81 is engageable with the lifting bar |63 carried by the ram 13 so that upward movement of the ram will lift the lower arm. The upper arm 88 is provided with a downward extension |04 carrying a roller |66 at its free end which bears on the fiat upper surface |61 of the transverse extension |68 formed on the lower arm. This provides for the upper arm to add its weight to that exerted by the lower arm on the spring system 2| and minimizes frictional drag between the two arms.

In operation, as the ram 13 is lowered the weight of both arms will rst be applied to the spring system 2| and then at a lower ram position the weight of the upper arm 88 will be removed. This is accomplished by the coaction of the hooks 82 and |69, lever and pin ||2. The 'hook |89 and lever are mounted and fulcrumed, respecmounted on the back side of the tively, on the upright member ened to the plate 86 by a bolt I4, as shown in Fig. 6. The end of the lever which engages the pin 2 is somewhat longer and, therefore, heavier than the opposite end so that the lever is urged in a counterclockwise direction about the pivot pin l I6 by gravity to normally clear the pin 2, thereby preventing the lever from disturbing the load applied by the upper arm. The

stationary khook |99 functions as a stop to limit counterclockwise movement of the lever so it cannot be rotated beyond the position where it can be engaged by the movable hook 32 on the rack. As the ram moves downwardly there will at rst be a period during which both arms load the spring. As the ram continues to move downwardly the movable hook 82 will engage the lever il and rotate it around the pin I6 until the opposite end of the lever ili engages the pin l2 upper arm 63. Further downward movement of the ram will then 'cause the lever to lift the upper arm from the lower. Weights ||1 and I8 are provided for the loading arms 81 and 98, respectively, and may be adjusted suitably along the length of the arms to apply a desired loading force to the spring system 2| Combined holding and contacting mechanism is provided for the switch being adjusted. This mechanism is best sli-own in Figs. 14, 15, and 16, and comprises a plate H9 mounted on the plate 66 by means of bolts |2| (see also Fig. 3). A pair of similarly formed but oppositely facing side members |22 are mounted on the plate i9 and a strut |23 serves to tie them together at one end, the side members i 22 and strut |23 being fastened together and onto the plate H9 in any suitable manner, as for example, by silver soldering. It will be noted by reference to Fig. 11 and Fig. le that the lower side edges |24 and |26 at opposite ends of the particular switch casing shown are at diierent levels so that they must be supported at different heights to maintain the switch normal to the ram 13 during adjustment. To this end grooves |21 are -cut interiorly of the side members |22 and longitudinal inserts |28 are mounted therein by screws |29. The cross-section of the inserts 26, generally L-shaped, have an inwardly extending shoulder 3| at one end engageable with the switch casing edge |24 and having a similar shoulder |32 at a lower level (best shown in Fig. l5) which is engageable with the lower switch casing edges |26. The inserts |23 may be readily replaced by others to accommodate switch housings of different dimensions, thereby making the adjusting mechanism applicable to a wide variety of switch sizes and shapes. To hold the switch in place during adjustment a holding lever |33 is pivoted on a pin |34 fitted in a cut-away upper corner |36 of each of the side members |22. Each lever |33 is formed with a lower vertical portion |31 urged outwardly by a coil spring |38 which is tted within shallow aligned bores in the lever vertical portion and the corresponding side member. At the upper end each holding lever |33 is formed with a horizontal lip |39 extending inwardly beyond the side member |22 andy engageable with the upper edge of the switch housing (see Fig. 16) to hold the latter in place. A

Vchamfer |66 is provided at the leading edge of each lip |39 to facilitate ready insertion of the switch.

Means for incorporating the switch undergoing adjustment into the electric control circuit (which Will be described subsequently) is provided by the ||3 which is fast- -an alternating current generator.

source of electric current contact carrying member |14! which comprises Ya base |42 of electrical insulating material oi suit able strength, mounted on the plate I9 between the side members |22 as by a screw |43. Rive-ted onto the top side of the insulator |42 are three inwardly extending arcuate leaf spring contacts |44, |46 and |41, so positioned that when the switch is mounted as show-n in Fig. 16V they engage respectively the terminal screws vl5, I6, and '22' or the terminal tabs |1, |8, and 23.

Switches of this type tall into three general classes: double throw, such as show-n in Fig. 9, in which the common terminal 23 is normally connected to terminal |1 but which may be connected to terminal I8 by holding the plunger 34 depressed; normally open, in which stationary contact 13 is replaced by a non-conducting stop and terminal |1 is omitted, o'r the vterminal |1 is simply not used; and normally closed, in which the stationary contact |4 is replaced by a nonconducting stop and terminal A|8 is omitted, or the terminal |8 is not used. In practice, it will be preferable to provide an electrical circuit for the adjusting mechanism which will permit any of these three types of switches to be adjusted. To provide a clearer understanding of the operation of the adjusting mechanism two simplified circuits, Figs. 17a-d and 18a-d, will first be described showing how in one case the invention may be applied to adjusting double throw or normally open switches and in the other casel to normally closed switches. After these simplied circuits are described attention will then be directed to a more complicated circuit which combines both the simplified circuits in such a way that the invention may be applied to adjust either double throw, normally open, or normally closed switches as desired.

In Figs. 17a-d a simplified circuit for the above `described mechanism is shown in the successive operative positions for adjusting a double throw or normally open type of switch. This circuit is designated hereinafter as the A circuit. The normally closed preloading switch |48 which remains closed when the operating handle 5`3` -is in its raised position is connected in series with the magnetic clutch 42 and a source fof electric current |49 through the conductors |'5|, |52, and |53. The source of current |49 may comprise ra battery or in the event that it is desired to test the switch 2|a with direct current or if it is to be tested with alternating current the source |49 may be The .switch being adjusted, designated here as 2m, .is connected through conductors |54 and |56 in shunt with the preloading switch |48. In the present instance, the switches 2|a and |48 are shown as both being connected in series with the same |45 but in practice where it is preferred separate sources of current may be employed provided that the clutch 42 iis in series with each switch. Thus, in the particular circuit shown in Fig. 17a both switches 2h11l and |48 are in parallel with one another but each is in series with the clutch 42 so that the latter may be separately energized through either. Switch |48 is referred to as the preloading switch because in operation it serves to energize the coil of clutch 42 until the loading arms B1 .1

and 88 (Fig. l) are veffective to snap the spring system 2| to its abnormal position when the clutch is energized through the switch Bla.

Considering now the operation` of the mechanism employing the simpliiied 'circuit A, assume a rectifier connected to an A. C. l-ne f 8 that a double throw switch such as shownin Fig. 9 is to be adjusted. The upper stationary contact |`3 will serve only asa stop since the terminal l1 will not be connected. Thus, the switch will behave exactly as a normally 'open switch and for this reason adjustment procedures for double throw and normally open switches are identical. Initially the clutch arm 39 and operating lever 5| will be in positions shown in Fig. 11a and the clutch coil 43 will be energized Ythrough the preloading switch |48; Movement of the operating handle 53 upward will cause the armature 52 to be attracted by the clutch member 42. Movement ofthe handle 53V and clutch lever 39 downward to the position shown in Fig. 17h will then lower the arms 81 and 88 so they are both eiective to load the 'spring system; the combined weights ||1 and ||8 will apply a predetermined load to the spring system to snap the switch to its abnormal or closed position (see Figs. Z-l and 21a) so the clutch coil will now be energized through both switches 2|a and |48. Further downward movement of the handle to the Fig.. l'lc position causes the end of the operat ing lever to engage the preloading switch and open it so that the clutch coil is energized only through the switch being tested. Further movement of the handle will cause the upper arm to be liited by lever so that only the lower arm 81 is effective to load the spring system (see Figs. '22 and 22a) the weight |1 being such that the load applied by the lower arm alone is substantially equivalent to the desired release force to be applied by the plunger 34 (Fig. 9') after the switch is assembled. The release force for the switch is the downward force on the plunger 34 will just allow the spring system to snap 'from its abnormal to its normal position. Still furthe nal downward movement of the handle to the position shown in Fig. 17d forces the ram 13 down upon the ends of the anchor 32 (see Figs. 223a1'1d 23a) and bends the legs 11 so that the pivot grooves 33 cross the tension element 24 whereupon the spring system 2| snaps upwardly to its' normal or 'open position. This deenergizes the clutch coil nullifying its attraction for the armature A52 and, therefore, further movement of the operating lever is ineffective 'to- 'deform the switch anchor.

In Figs. 18a-d another simplified circuit, hereinafter designated 13, yfor the adjustment of normally closed switches, is shown. This is basically the same circuit as that just described for double throw normally open switches except that a normally closed relay is employed to deenergize the clutch coil when the switch 2|a is in its normal or closed position. As in the previous case, the normally closed preloading switch |48 is connected in series with the clutch 42 and the source of current |49 through conductors |5|, |52 and |53 a sub-circuit in parallel with the subcircuit containing the preloading switch and clutch includes the conductor |54, switch 2|a, to vbe adjusted, conductor |51, relay coil |58 and Vconductor |59; and a third sub-circuit in parallel with switch |48 includes the conductor |6|, the normally closed relay switch |52 and the conductor |63.

Considering now the operation of the mechanism of the present invention employing the simplified B circuit shown in Figs. 18a-d, assume that .the switch to Abe adjusted designated .2|a is .a normally closed switch. This again may `be a switch similar yto that shown in Fig. 9v` with the lower stationary contact |4 either unused or replaced by a non-conducting stop. Initially the clutch arm 39 and the operating lever 5| will be in the position shown in Fig. 18a and the clutch 42 will be energized through the sub-circuit including the preloading switch |48; the relay switch |62 will be held open -by the energized coil |58. Movement of the operating handle 53 upward will cause the armature 52 to be attracted by the clutch member 42. Movement of the handle and clutch lever downward to the position shown in Fig. 18h will then lower both arms 81 and 88 to place their combined weight on the spring system (see Figs. 21 and 21a) this will snap the switch to its abnormal or .open position so the clutch coil will be energized through both the preloading switch |43 and the relay switch |62 which will now be closed due to the deenergization of the relay coil |58 by opening switch 2| a. Further downward movement of the handle to the |80 position causes the end of the operating lever to engage the preloading switch and open it so that the clutch 42 is energized only through the relay switch |52. Further movement of the handle will cause the upper arm to be lifted by lever I so that only the lower arm 81 is eiective to load the spring system, this load being substantially equivalent to the desired release load as above mentioned. Still further, final downward movement of the handle to the position shown in Fig. 18d forces the ram 13 down upon the ends of the anchor (see Figs. 23 and 23a), and bends that part so that the pivot grooves 33 cross the tension element 24, whereupon the spring system snaps upwardly to its normal or closed position; this closes the subcircuit |542|a|51|58|59 to energize the relay coil which in turn opens the relay switch |62, thereby deenergizing the coil of clutch 42 and releasing the clutch lever 39 from the operating lever In actual shop use, it is preferable to combine Iboth the A and B simplied circuits so that the mechanism may be readily applied to the adjustment of either double throw, normally open, or normally closed switches. They may be so combined as shown in the wiring diagram illustrated in Figs. 19a-h, this wiring diagram being designated for convenience herein as the AB circuit.

Figs. 19a-d show the AB circuit as it is applied n to the adjusting of a double throw or normally open switch; and Fig. 19e-hl show the AB circuit as it is applied to adjusting the normally closed switch. In each of the circuits illustrated herein heavy lines are employed to designate that part of the circuit that is energized.

It will be noted that when the selector switch is moved to the DfT-NO position, as sh-own in Fig. 19a, the eiective part of the AB circuit is the same as that shown in Fig. 17a, namely, with the preloading switch |48, the clutch 42 and the source of electricity |49 connected in series. Likewise, Figs. 19h, 19e, and 19d show how the effective parts of the AB circuit are identical with the A circuit in the various operative positions shown in Figs. 11b. 17e, and 17d, respectively.

It will be further noted that when the selector switch |54 is moved to the NC position to convert the mechanism to adjustment of normally closed switches the eective parts of the AB circuit as shown in Figs. 19e, 19j, 19g and 19h are identical with the B circuit in the various operative positions shown in Figs. 18a, 18h, 18e and 18d, respectively.

Operation The 'operation ofthe switch adjusting mech-V similar sequence of operations for adjusting anormally closed switch.

A double throw switch, such for example as shown in Fig. 9 but with the cover 2 and plunger 34 removed, will be inserted between the side members |22 of the holding mechanism shown in Fig. 4. The end of the switch being adjusted will abut the tie bar |23. Its top edge will be engaged by the spring pressed fingers |39 of the holding levers |33. Bottom edges |24 and |26 of the switch will rest respectively on the shoulders |3| and |32 of the inserts |28. And the switch terminal screws |5, I6 and 22 will be engaged respectively with spring ngers |44, |46 and |41 which in turn are connected to conductors |19, |18 and |54. Initially, the clutch 42 will be moved to its uppermost limit (Fig. 2) by the weight 66 acting on the pulley sector 59 (Fig. 3). The counterbalancing end portion 56 of the operating lever 5| approximately as shown in Fig. 2. As shown in Figure 1 and Fig. 20 both the ram 13 and the weighted arms 81 and 88, which are supported on the ram by means of pin |02 and bar |93, are retracted upward from the switch being adjusted which is designated 2|a and (see Fig. 20) the spring system 2| in the switch 2 la is in its normal position with its movable contact |9 pressed against the upper stationary contact I3. The

anchor 32 will have been formed, preferably prior to assembly in the switch, with its pivot grooves 33 above their correct position so that downward movement of the ram 13 in carrying out the adjusting operation will bend the legs 11 downward until the grooves are correctly positioned.

To condition the mechanism for adjusting a double throw switch the selector switch |64 will be closed on the DT-NO side. Adjustment of the switch 2|a will then be carried out entirely automatically by first moving the operating lever upwardly suiciently to engage the armature 52 by the clutch 42 and then pulling the handle downward in one steady sweep until the clutch 42 is automatically deenergized, as wil1 be described, by release movement of the spring system 2| in snapping from the abnormal to normal positions to signify that the adjusting operation has been completed. The speed of downward movement of the handle 53 during adjustment is regulated by the dashpot mechanism shown in Fig. 3 as is also the speed of upward movement of the clutch lever 39 responsive to the pull of weight 56 when the armature is released at the end of the adjusting operation.

At the start, the coil of clutch 42 will be energized through the preloading switch |48, as shown in Fig. 19a. That part of the circuit which places the preloading switch and the clutch in series with the current source may be traced as follows: |49|5||66|48|61414246|1I.

As the operator pulls down the handle 53 the rack 38 on which the ram 13 is mounted is moved downwardly. At the position shown in Fig. 19h and Fig. 21 the lifting bar |63 will have moved downward away from the pin |02 on the lower arm and, since the upper arm 88 likewise bears on the lower arm through the roller |35, the weight of both arms 81 and 88 will be effective will urge the latter to a normal position.

on the tension elementg@V to operate the spring to its. lower or abnormal position as shown in Fis 21a where the carried Contact I9 is engaged by the lower stationary contact |4. The coil of the clutch 42 will now be energized through both the preloading switch |68 and switch ila (Fig. Y19o). That portion of the circuit which. planes. the nreloading switch and the clutch in series with the Current source may be traced exactly as outlined in the above. paragraph. That portion of the eireuit which places the switch being adjusted in series with the oluteh may be traced as follows: l49-15legst-2malrsflsdmfu-az-asfl1|. rf preferred, these two parts of the circuit may be energized by Separate current sources. Furthermore', if neoessary the olutoh means represented by the oluton 42 may talse the form of. separate clutch coils energized by the Separate current SOllICeS.

Further downward movement o f the rack 38 and the hook 82 attached thereto will cause the lever to lift the upper` arm 88 from the lower arm surface |01 (Fig. 22) the load applied by the lower arm being preselected to be equivalent to a desired release load for the switch; this further movement win also causel the. widened end 5d o f the operating lever 5| to overrun the actuating arm 51 of the preloading switch (see Fig. 8 for the relative dimensions of the actuating arm and the end of the opera-tins lever), and will hold the pre'loadine switch open. for the .remainder of the downward movement of. the operating handle el. That. non tion oi the .circuit places, the switch beine adjusted and the clutch. in series with the ourrent source is the same that traced in. thepreoedins paragraph. As shown in Tise 22d the .spring system 2| will remain inl its lower or abnormal position. after the lifting of the upper arrn. 88,.

Still further downward movement of the rain le, with the desired release load beine applied to the spring system 2l 'by the. lower .arno 81 at the plunger loading point. will prins the. rain into Contact with the ends of the anchor lees 11 (Fis. .23) and the latter will be deformed downwardly until the pivot grooves 33 arel mov-ed beyond the plane oi the tension element 24 whence the .spring system will release. that will .snap upwardly to its normal position as shown in Fle- 23a.. et. this time, as .shown in Fie.

19d, the. ooil of oluton 4.2. is deenersized. thereby breaking the electromagnetic oonneotion between the operating and eluton levers 5l and 39. The oluteh lever 39. is. tuen moved upward by the weight SS. and when the operator releases the handle 53 it also moves upwardly and the parte resume their .original positions shown li'ie- 2. and are ready for another adjusting. oyole.

To adjust a normally olosed switch with this meohanism the procedure on the part of the operator is exactly the same except that he rst.

closes the N C side of the selector switch |64. Fig. 19e is the circuit at the beginning of the adjust.- ment operation for the normally closed switch, the coil of clutch 42 being energized through the preloading switch |48 and the relay coil |58 being energized through the. switch 2.|a being ad-v justed. That portion of the circuit which places the preloading switch and the clutch in series with the source of electric current may be traced as portion of the circuit which places the switch being adjusted and the relay coil in series with the source of electric current may be traced as follows; ide-lEl-Ill-Z|`a|79|64|13|53|12|1L As has been explainedgreviously, sepa-rate sources of electricity may be employed for these two parts of the circuit if desired. Fig. 19j shows the circuit after the parts have been moved down to the Fig. 21 and 21a positions where both arms 8? and 88 are effective to load the spring system 2| sufficiently to snap it down to its abnormal position, the clutch coil now being energized through both the preloading switch |63 and the relay switch le?. That part of the circuit which places the preloading switch and the clutch in series with the source of current is traced exactly as outlined in the preceding paragraph. That portion of the circuit which places the relay switch in series with the clutch and the current source may be traced as follows:

Fig. 19g shows the circuit after the operating lever 5| has moved to open the preloadingr switch |138 so that at this time the clutch coil is energized only through the relay switch, as traced above. Also, at about this time, as shown in Figs. 22 and 22a, the upper loading arm 83 will be lifted leaving only arm 3i' applying a desired release load to the spring system.

Fig. 19h shows the circuit after the ram has moved down to engage the anchor (Figs. 23 and 23a) and has deformed the latter suihciently to cause the spring system to snap upward to its normal position and engage the stationary contact I3, thereby energizing the relay coil |58 which in turn opens the relay switch |62 and deenergizes the coil of clutch 42. That part of the circuit which now places the switch being adjusted and the relay coil in series with the current source may be traced as follows:

After the clutch d2 has been deenergized in this manner the ram 13, arms S1 and 38, clutch and operating levers 39 and 5| will be retracted to their original positions shown in Figs. 1 and 2.

Now, for the salie of simplifying the descrip tion, it nas been stated that the load applied to the spring by the lower arm 8'! will be adjusted to a value substantially equivalent to the desired release load which will subsequently be applied by the plunger Sil when the switch is assembled. Actually, the load applied by the arm 8l must be in excess of the desired release load, to an extent determined by experiment for each design of anchor, SO. aS to compensate for the resilience or spring-back of the anchor when the deforming load is released. Furthermore, while I have described the present invention in connection with means for actually permanently deforming the anchor legs Tl, it will be obvious that in some types of spring mechanisms it may be preferable to move or tip the entire anchor or spring support in the desired direction rather than locally deforming it; the basic principle of the present invention resides in permanently moving a supported portion of the spring system to elect automatic, closely controllable adjustment of the switch mechanism. Furthermore, while the invention has been illustrated as applied to the adjusting or a specific type of spring system' in a specied type of electric switch, it will be obvious that it may be applied to the adjustment of many other speoic types of spring systems whether in electric switches or not.

Thus, while a particular arrangement of parts has been shown to illustrate the present invention, it will be apparent that changes therein will readily suggest themselves to others skilled in the 13 art without departing from the spirit and scope of the invention. Having thus described the invention, what is claimed as new is:

I claim:

1. Apparatus for adjusting an assembled spring mechanism having a snap acting spring system movable between two positions and a separate xed support member for a portion of said spring system comprising means for applying a preselected load to the spring system, means for permanently moving the support in a direction to initiate movement of said spring system from one to the other of said two positions while said preselected load is applied thereto, and means responsive to said initiated movement of said spring system for terminating the operation of the last mentioned means and the permanent movement of said support.

2. Apparatus for adjusting a spring mechanism of the self-returning ty 3e having an overcenter snap spring system movable between normal and abnormal positions and a support for said spring system, comprising means for moving said spring system to abnormal position, means for applying to said spring system while in abnormal position a load determined in accordance with a predetermined release load, means for permanently changing the position of said support concurrent with the application of said load to the spring system while in the abnormal position to initiate movement of said spring system from abnormal to normal position, and means responsive to the movement of said spring system from abnormal to normal position to limit the permanent change in position of said support.

3. Apparatus for adjusting a self-returning spring mechanism having an overcenter spring system movable between normal and abnormal positions, said spring system having a support therefor initially spaced from a preferred position, said spring system adapted to move from normal to abnormal position responsive to application of a certain operating force thereto and adapted to move from abnormal to normal position when the force on said spring system is diminished to a certain release force, said apparatus comprising means for applying to said spring system a load in excess of its operating force to cause it to move to abnormal position, means for diminishing the load on said spring system to a value determined by its release force, means for permanently moving said support toward its said preferred position concurrently with the application of said diminished load on said spring system to initiate the movement of said spring system from abnormal to normal position, and means responsive to the movement of said spring system to noru mal position to terminate the movement of said support at said preferred position.

4. Apparatus for adjusting an assembled snap acting mechanism having a support and an overcenter snap spring system with a portion thereof pivotally mounted on said support, comprising means for applying a preselected load to said spring system and means for concurrently applying a force to permanently move the portion of said support pivotally engaged with said spring system.

5. Apparatus for adjusting an assembled selfreturning type of snap acting mechanism having an overcentersnap spring system with a portion thereof pivoted on the free end of a support, comprising means for applying a preselected release load to said spring system and means for concurrently applying a force to the free end of said I4 support to move the pivoted portion thereof to a preselected permanent position.

6. Apparatus for adjusting an assembled snap spring mechanism having a support and an overcenter snap spring system supported thereon and movable with respect thereto, comprising means for applying a preselected load to a portion of said spring system and means for concurrently applying a bending force to said support to bend it permanently to an extent determined by snap motion of said system under said preselected load.

'7. Apparatus for adjusting the spring mechanism of an electric switch having a contact movable by a spring system between two positions with respect to another contact and having supporting means for said spring system, comprising loading means for applying a preselected load to said spring system while it is in one of said two positions, means for moving the supporting means while said loading means is effective on said spring system to initiate the movement of said spring system to the other of said two positions, and means responsive to the movement of said spring system to said other position for limiting movement of said supporting means.

8. Apparatus for adjusting an electric switch having a contact carried by an over-center snap spring system between two positions with respect to another contact, operating means engageable with said spring system, and means for supporting said spring system for snap movement with respect thereto, comprising means for preselectively loading said spring system at the position where said operating means would normally be engaged, means for permanently moving the supporting means while the preselected loading is effective on the spring system to initiate snap movement of said spring system from one to the other of its said two positions, and means dependent on the movement of said spring system between said two positions for terminating permanent movement of said supporting means.

9. Apparatus for adjusting a switch having a contact movable by a spring system through an unstable position of maximum stress between preselected switching positions, and deformable supporting means for a portion of said spring system, comprising means for applying a preselected force to that portion of said spring system where the operating force would normally be applied, means effective concurrently with the application of said preselected force for permanently deforming said supporting means to cause said spring system to move between said switching positions, and electromagnetic means controlled by the switch being adjusted for limiting the deformation of said supporting means in response to said movement of said spring system between switching positions.

10. Apparatus for adjusting a switch having a contact movable by an overcenter snap spring system in a snap action manner between normal and abnormal positions with respect to another contact, and a deformable support for a portion of said spring system, comprising a movable actuating member, means responsive to movement of said actuating member for applying a preselected load to said spring system to move it from normal to abnormal positions, means responsive to movement of the actuating member for applying a second preselected load to said spring system, means operably associated with said actuating member and effective concurrently with the application of said second load for deforming said support to cause said spring system to snap tosaid normal position, and means for terminating the deformation of said support when said spring system is snapped to said normal position.

11. Apparatus for adjusting a switch having a contact movable by an overcenter snap spring system between nor-mal and abnormal positions with respect to another contact and a support for a portion of said spring system comprising means for applying a load to a movable portion of said spring system suiiicient to move it from normal to abnormal positions, means for subsequently applying a preselected load to said spring system above a specified release force for the particular system, means effective concurrently with the application of said preselected load for permanently `bending said support to cause said spring system to return by snap action to said normal position, and electromagnet means controlled by said switch for stopping the deformau tion of said support when said spring system is returned to said normal position in response to the bending of said support.

l2. Apparatus for adjusting a self-returning type of switch having a contact movable by an.

overcenter .snap spring system between a normal and an abnormal position, a second contact engageable by said movable contact in one of said positions, and a support for a portion of said spring system, comprising: means for moving the I spring system from normal to abnormal position; means for loading said spring system with a load dependent on a kpredetermined release force for the assembled switch; a ram element engageable,` with said support; means for moving said raml element to deiorm said support to snap said spring system from abnormal to normal position; and means for terminating the operation oi the last mentioned means in response to movement oi the springsystem from abnormal to normal position.

13. Apparatus for adjusting a self-returning type of switch having a contact movable by an overcenter snap spring system between a normal and an abnormal position, a second contact engageable by said movable contact in one of said positions, and a support for a portion of said spring system, comprising: means for moving the spring system to abnormal position; means for loading said spring system with a load dependent on a predetermined release force; deforming means dependent on the electrical energization of electromagnet means for deforming said support; means for moving said deforming means to deform said support to snap said spring system from abnormal to normal position; and means for deenergizing the electromagnet means in response to movement of the spring system from abnormal to normal position, to prevent further deformation of said support.

14,. Apparatus for adjusting the assembled spring mechanism of a switch having normal and abnormal positions and having a contact carried by an overcenter snap spring system, a second contact engaged by said carried contact in one of said positions, and a support for a portion of said spring system, comprising: means imparting permanent movement to said support, loading means movable upon movement of said support moving means to apply preselected loads in predetermined sequence to said spring system, movable Operating means, an electromagnetic clutch for retaining the support moving means and the, operating means in engagement, preloading switch means for initially connecting I said deforming means to cause said clutch means to a source of electric current to energize the clutch and render said loading means and said support moving means operable in response to movement of said operating means, means responsive to movement of said operating means in a direction to move said support for rst -causing said loading means to move said spring system to its abnormal position and then loading the spring system a predetermined amount depending on a desired release force, and means responsive to movement oi said spring system from abnormal to normal positions upon movement of said support by said `support moving means for deenergizing said electromagnetic clutch means and thereby limiting further permanent movement of said Support by force exerted upon said operating means.

l5. Apparatus for adjusting double throw and normally open switches having normal and abnormal positions and having a contact movable by an overcenter snap spring system, a second contact engageable by said movable contact in said abnormal position, and a deformable support for a portion of said spring system, comprising means for applying a deforming load to said support, loading means operable concurrently with movement of said deiorming means for applying preselected loads in predetermined sequence to said spring system, movable operating means connected to said deforming means through an electromagnetic clutch, a normally closed preloading switch positioned to be opened by said operating means when the latter is moved in a direction to move said deforming means to deform said support, said preloading switch and the switchy to be adjusted being connected in parallel with one another and in series with said clutch, whereby movement of said operating means is effective through said clutch to move said loading means to move said spring syste-m to its abnormal position, and whereby upon further movement of said operating means the load on said spring system is reduced and said deiorming means is elective to deform Said spring support surliciently to move said spring system to its normal position to deenergize the clutch and thereby limit deformation of said support.

16. Apparatus for adjusting double throw and normally open switches having normal and abnormal positions and having a contact movable by an overcenter snap spring system, a second contact engageable by said movable Contact in said abnormal position, and a deformable support for a portion of said spring system comprising means for applying a deforming load to said support, loading means operable concurrently with movement of said deforming means for applying preselected loads in predetermined sequence to said spring system, movable operating means connected to said deforming means through an electromagnetic clutch, a normally closed preloading switch positioned to be opened by said operating means when the latter is moved in a direction to move said deforrning means to deform said support, saidv preloading switch being connected in series with the electromagnetic clutch and the switch being adjusted being conu nected in shunt with said preloading switch, whereby said `clutch is normally energized through said preloading switch but upon progressive movement of said operating means in a direction to, cause said deforming means to deform said support, said loading means is caused to apply a load to said spring system to move i the latter from its normal to its abnormal position thereby energizing said clutch through the switch being tested whereby upon further movement of said operating means said preloading switch is opened, thereby energizing said clutch solely through said switch being tested, and whereby upon still further movement of said `operating means said deforming means is caused to deform said support suificiently to snap said spring'system to its normal position, thereby deenergizing the clutch and preventing further deformation oi said support.

A17. Apparatus for adjusting double throw and normally open switches having normal and abnormal positions and having a contact movable by an overcenter snap spring system, a second contact engageable by said movable contact in said abnormal position, and a deformable sup- 'port for a portion oi said spring system comprising means for applying a deiorming load to `said support, loading means operable concurmeans to deform said support, said switch being,

adjusted and the coil of said electromagnetic clutch and a source of electric current being connected in series, the preloading switch and said clutch coil and a source of electric current being connected in series, said operating means being movable through the following operative positions in a direction to cause deformation of said support; a position where said clutch coil is ,energized through said preloading switch; a position where said loading means is responsive to movement of said operating means to load said spring system to move the latter to its abnormal position, thereby energizing the clutch coil through the switch being adjusted; a position where said preloading switch is opened whereby said clutch coil is energized solely through said switch being adjusted; a position where said loading means is effective in response to movement of said operating means to reduce the load on said spring system to a predetermined release force; and a position where said deforming means is eie'ctive in response to movement of said operating means to deform said support suiciently to move said spring system from its abnormal to its normal position, thereby deenergizing the clutch coil and causing the clutch to release the operating means.

18. Apparatus for adjusting normally closed switches havinf-,r normal and abnormal positions and having a contact movable by an overcenter snap spring system, a second contact engageable by said movable contact in said normal position, and a deformable support for a portion of said spring system, comprising means for applying a deforming load to said support, loading means operable concurrently with movement of said deforming means for applying preselected loads in predetermined sequence to said spring system, movable operating means connected to said deforming means through an electromagnetic clutch, a normally closed preloading switch positioned to be opened by said operating means when the latter is moved in a direction to move said deforming means to deform said support, and a relay having a coil and a normally closed switch 18 operable in response to energization of said coil; said relay, said electromagnetic clutch, said preloading switch and the switch being adjusted being connected by an electric circuit having first, second and third sub-circuits, the first subcircuit having the preloading switch and the electromagnetic clutch in series, the second subcircuit being in parallel with the first sub-circuit and having the switch being adjusted and the relay coil in series, and the third sub-circuit having the relay switch in parallel with the preloading switch; whereby movement of said operating means is effective through said clutch to move said deiorming means to cause said loading means to move said spring system to its abnormal position, and whereby upon further movement of said operating means the load on said spring system is reduced and said deforming means is effective to deform said spring support suiilciently to move said spring system to its normal position to deenergize the clutch and thereby limit deformation of said support.

19. Apparatus for adjusting normally closed switches having normal and abnormal positions and having a contact movable by an overcenter snap spring system, a second contact engageable by said movable contact in said normal position, and a deformable support for a portion of said spring system comprising means for applying a deiorming load to said support, loading means operable concurrently with movement of said deforming means for applying preselected loads in predetermined sequence to said spring system, movable operating means connected to saidgdeforming means through electromagnetic clutch means, a normally closed preloading switch positioned to be opened by said operating means when the latter is moved in a direction to move said deforming means to deform said support, and a relay having a coil with a normally closed switch operable in response to energization of said coil; said preloading switch being connected in series with the electromagnetic clutch, the switch being adjusted and the relay coil being connected in series with one another and in parallel with that part of the circuit containing the preloading switch and the electromagnetic clutch, the relay switch being connected in parallel with the preloading switch, whereby said clutch is normally energized through said preloading switch but upon progressive movement of said operating means in a direction to cause said deforming means to deform said support said loading means is caused to apply a load to said spring system to move the latter from its normal to its abnormal position thereby energizing said clutch through the relay switch whereby upon further movement of said operating means said preloading switch is opened, thereby energizing said clutch solely through said relay switch, and whereby upon still further movement of said operating means said deforming means is caused to deform said support suiiiciently to snap said spring system to its normal position to energize said relay coil to deenergize the clutch and prevent further deformation of said support.

l 2'0. Apparatus for adjusting a normally closed switch having normal and abnormal positions and having a movable contact carried by an overcenter snap spring system, a second contact engageable by said carried contact in said normal position, and a deformable support for a portion of said spring system, comprising means for applying a deforming load to said support, loadgewas-741 t9 ing means operableconcurrently Awithl movement of said-deformingrmeans for applying preselect- Yed loads inpredetermined-sequence to said spring system, movable-operating -means connected to ,said deiorming :means vthrough an electromagnetic clutch, a normally closed preloading switch positioned tobe opened by said operating means xlwhenlthe latter is moved in a direction to move said deforming means to fdeform said support, Aanda relay having a coil `with a normally closed switch operable in response to electrical energization of said relay coil, said'preloading switch being :connected .inseres withsaid clutch coil and a :source of electric current, said lrelay switch being connected Lin shunt .with said preloading l.-switch, said switchbeingadjusted being connect- `:edin series-withfsaid'relay-coil and ra source of *electric current, said-operating means being movable through kthe following operative positions -in adirection-tocause-deformation of said sup-f; port; a position where said Vclutch coil is energized through said preloading switch; a po- "sition where said Aloading means is responsive *tomovement of saidoperatingmeans to load said "spring systemto move'thelatterto itsabnormal position,` thereby energizing the clutch coil both `through -the preloading switch and the relay switch; la `positionwlieresaid preloading switch is opened whereby said'clutch-coil is energized solely through said relay'switch; aposition where said loading rmeans is effective in response to movement of said operating means to reduce theloadon saids'pringsystem to a 'predetermined release force; and a "position where said deforming-means is-eifective'in response to move- -ment of said 4operating 'means *to Vdeform said support rsu'lciently to cause said spring system `fto be movedirom its'abnormal to its ynormal position,'thereby-energizinglthe'relay coil to open `therelayswitcnand deenergizingthe clutch coil l to causethe clutch to-release the pperating'means.

y2l. VApparatus "for adjusting the assembled rspring'mechanism-of 'alswitchhaving an overeen- 'ter snapspringsystemfmovable between two'posi- A.tions anda supportfor said `spring'system com- .:prising support'moving means 'movable Vbetween va -retracted position 'and Aa position operative on `said support 4for moving the same to an adjusted lpos'itiontoisnapthe spring'system from said one position -to i the other position, 'movable operating .imeansfav clutch releasallyl connected between said :support movingfmeansf-an'd said operating means, `said support movingmeansbeingreleasable from :said operating .means Vin Aresponse to movement y' lof said spring system irom'said one position to the -other position, loading i means -for said` spring system movable concurrently 'with movement of :said support moving fmean's for applying to said spring inthe operative position of the support .moving-means'a loaddependent upon a predetermined frelease force "for the assembled spring mechanism, and Ameans orreleasing said clutch 'in 'response to theaforesaid snap movement of ithespring systemtoterminate movement oi said support. A

22. Apparatus -for adjusting the assembled :spring mechanism ofaswit'ch having a contact movable lby 1an I-overcenter snap spring system between two positions,-a secondcontact engageable-by said movablelcontactinone of said positions, and a supportfor saidspring system, comprising means-movable between afretractedposi- Ytion and a position .operative on said supportfor permanently movingfsaid support, a clutch, mov- "able operating means-effective to move'the sup- ;,port moving-means through said clutch, and 'an electric circuit including said switch contacts operative vto release said clutch upon opening of the circuit by movement of the movable Contact away from the second contact whereby when said support is permanently movedto an extent suiiicient tocause said 'spring system to snap v`from said one position to the other position said clutch lis disengaged Ito prevent further permanent movement of said support.

23. Apparatus for adjusting 'an assembled mechanism having an overcenter snap spring system with a portion-free :to move between preselected positions and a support for 'mounting saidspring system including a bendable member (comprising means movable bodily between preselected .positions for deforming the bendable member, means controlled by said latter means andengageable with said springrsystem before the deforming means Vengages"` the bendable memberfor applying a .load .tozsaidspring system :to move said free portion of the spring system to a preselectedvone ofits positions, means operable upon predetermined im'ovement :of said deforming means for releasingfa'portion of said load ap- 'plied to the spring system, manual means for effecting movement of said deforming means in ra :direction 'to Adefornrsaidbendable member to 'rmovesaid spring system iovercenter to move said #free end portion to its other position, means for -disengaging said-manual means from the deform- 40-:ing means when said first portion moves from l'said one to itsother position, means ior moving the deforming means in a 'direction away from the bendable'member upon disengagement of the lmanual means and the deiorming means, land rmeans lforcontrollingthe .speed of movement of the deformingmeansinboth directions oi moveiment.

ROBERT W. PASHBY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

